The goal of this project is to establish a database for comparative neuroanatomy of primates using high resolution magnetic resonance imaging (MRI). Thus far, 40 animals have been scanned, including representatives of every species listed above. Currently 20 of these scans have been reconstructed to provide surface rendering and volumetric measures of whole brain and whole cerebellum. A technique for gray matter/white matter segmentation has been developed and applied to a subset of these scans. Preliminary results demonstrate that apes and humans do not differ in frontal lobe size, corrected for whole brain volume. In addition, there does not appear to be an expansion of neocortical gray matter in humans relative to non-human primates. These studies, the first using in vivo quantitative neuroanatomy, may provide a new picture of differences and similarities of human and non-human primate brain structure.